A new mobile and Web app, called SoftStory, maps and highlights seismically vulnerable housing.

It’s been said the greatest dangers are the ones unseen. The maxim plays out aptly for Oakland, Calif., a city that recently rocked the news for its hundreds of residential buildings — and thousands of individual units inside them — prone to potential collapse in an earthquake.

The threat pinches a nerve for software developer Dave Guarino. For months Guarino has labored, half investigating and half collaborating, to develop an app that locates seismically vulnerable buildings. The new Web and mobile tool offers residents a quick way to check if their home could be vulnerable and lists each property’s current city evaluation status. Built within OpenOakland, a volunteer civic technology group, the app has mapped and color-coded high risk buildings based on data from the city and analysis by the Association of Bay Area Governments in 2013.

The app's name, SoftStory, stems from the term used to label susceptible structures built on slopes or squatting atop hollow infrastructure like apartments over empty parking garages. Guarino was compelled to coordinate development of the app partly from his association with OpenOakland but mostly from pressures close to home.

"I read about these problems that stem from seismic vulnerability, and then I realized, I was probably living in one of these buildings," he said.

The gravity struck Guarino deeply after he sifted through the information — building data that took roughly two months to gather from Oakland officials. What his analysis indicated was a glaring inequality between safe and unsafe homes in Oakland. Less affluent residents, those living in older multi-unit buildings, which comprise much of the city’s affordable housing, would be largely displaced in a large quake.

“In a major earthquake, if a lot of these buildings are not retrofitted and fall down, you're going to have a really significant displacement and it will disproportionately affect folks who are lower income,” Guarino said.

Worse, he added that based on current development trends and research, the displacement would likely be long term for many of Oakland’s less fortunate. Homes that had crumbled would not likely be rebuilt as affordable housing but return at market price with rents to match.

“Basically, that means a permanent displacement of a lot of people,” he said.

Putting his skills to work, Guarino and OpenOakland teamed up with Michal Migurski, CTO for the group’s parent organization at Code for America. Following the magnitude 6.0 quake that rattled California’s Napa Valley, Migurski volunteered to move the app along if only to engage the public on a critical issue.

"Mike said, ‘Hey, you've been working on this earthquake project, why don't we just sprint and get a quick version out,’” Guarino said.

And so, minus bells and whistles, Guarino and his team went to work coding data sets and mapping parcel information with a soft launch at the end of August. The idea is to draw attention and dialogue to the issue while calling on property owners to retrofit properties for themselves and residents.

Despite the endeavor, Guarino is realistic in his expectations. The issue is difficult and solutions hard. For one, retrofitting multi-unit buildings can generate contractor bills in the thousands for each unit. As example — and not as an average — he explained that if each unit had a retrofit cost of $15,000 this translates into a $75,000 cost for a common five-unit building. The price has to be shouldered by either building owners or unit residents, both of whom, might not be able to pay.

Second, the other challenge is held up in inspections: Structural engineers are required to definitively label a structure as a soft story building. Currently, a large majority of the potential soft story buildings mapped in the app have yet to finish a full inspection. There is also no law mandating property owners to retrofit buildings to modern standards — though city officials have said they expect an ordinance to come before year’s end.

As residents in potential soft story housing wait, Guarino said the best alternative is to invest in earthquake insurance that would help pay for lost property and provide temporary housing. Beyond this, public dialogue and calls for action are what he sees as the next best steps.

“This is a really complex issue — and I can't emphasize that enough,” Guarino said.